Linux Kernel Development, Third Edition

17. Devices and Modules

In this chapter, we discuss four kernel components related to device drivers and device management:

• Device types—Classifications used in all Unix systems to unify behavior of common devices

• Modules—The mechanism by which the Linux kernel can load and unload object code on demand

• Kernel objects—Support for adding simple object-oriented behavior and a parent/child relationship to kernel data structures

• Sysfs—A filesystem representation of the system’s device tree

Device Types

In Linux, as with all Unix systems, devices are classified into one of three types:

• Block devices

• Character devices

• Network devices

Often abbreviated blkdevs, block devices are addressable in device-specified chunks called blocks and ...